SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2768b69f34e682fcc1565af3803f875e508cd763c69218aee96a806742d6dc7' 
  AND token = 'hH2Gi2QsobmRPjz8lS8KNALopgI6hJvpByqp+ueNCh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}